1. Field of the Invention
The present invention relates to a cover for a hard disk drive case, constituting a hard disk drive by covering a case in which a storage device is enclosed.
2. Brief Description of the Prior Art
FIG. 9 is a side view of cover C1 for a hard disk drive in a prior art (hereinafter to be called xe2x80x98Coverxe2x80x99), and FIG. 10 is a plan view of Cover C1 which is seen from the inner side. FIG. 11 is an enlarged cross-sectional view of FIG. 10, cut along the line Axe2x80x94A, and FIG. 12 is an enlarged cross-sectional view of FIG. 10 cut along the line Bxe2x80x94B.
As shown in those figures, Cover C1 in a prior art is formed out of a laminated plate P1, having a damping resin material 3 closely inserted between an inner plate 1 and an outer plate 2 of stainless steel, equipped with a sealing material 4 for sealing between a storage device case (not illustrated) and laminated plate P1, and a tapped hole 5 to insert a screw for screwing laminated plate P1 to the case.
The above-mentioned laminated plate P1 has a three-layer structure composed of inner plate 1, outer plate 2 and damping resin material 3, wherein damping resin material 3 is exposed at the peripheral cross section of laminated plate P1.
Tapped hole 5 is a hole perforating laminated plate P1, and damping resin material 3 is also seen exposed on the inner wall of tapped hole 5.
Sealing member 4 is formed as a circular convex ridge on the surface of inner plate 1 according to the shape of aforementioned case, equipped with a non-slip stopper 6 formed monolithically with the convex sealing member through perforating hole 1c installed on inner plate 1. Sealing member 4 is installed on inner plate 1 before laminated plate P1 is fabricated.
However, the cover in the prior art has the following problems:
(1) Due to the structure wherein damping resin material 3 is exposed at the peripheral cross section of laminated plate P1 and on the inner wall of tapped hole 5, a rise of the ambient temperature of a hard disk drive causes damping resin material 3 to be softened to flow outside from between inner plate 1 and outer plate 2, thereby not only damaging the appearance and the quality of the hard disk drive but also depressing the damping function of Cover C1.
(2) Outflow of damping resin material 3 from the inner wall of tapped hole 5 caused by the rise of the above-mentioned ambient temperature makes laminated plate P1 around tapped hole 5 thinner, as shown in FIG. 13, and a screw 7 inserted to tapped hole 5 for screwing Cover C1 to above-mentioned case becomes loose, thereby weakening the fixing strength of Cover C1 to the case. If the screw is re-fastened for compensation of loosening, the damping resin is pushed out to depress the damping function of Cover C1 
(3) Since Cover C1 is fabricated of laminated plate P1 formed by inserting damping resin material 3 between the flat inner plate 1 and the flat outer plate 2, it does not have enough resistance against bending and torsion, that is, enough rigidity.
The present invention has been carried out in consideration of the above-mentioned problems in prior arts, to prevent outflow of the damping resin material and loosening of the screw inserted through the tapped hole to fix a cover to the storage device case, thereby preventing the depression of the damping function and the decrease in the strength of fixing the cover to aforesaid case, which improves the rigidity of the hard disk drive cover.
To attain the above-mentioned purpose, the hard disk drive cover of the present invention is fabricated of a laminated plate with a damping resin material closely inserted between an inner plate and an outer plate of metal, for covering a case enclosing a storage device by fastening with screws inserted through the tapped holes equipped on the laminated plate, wherein the sealing member is installed on the inner plate for sealing between the laminated plate and the above-mentioned case, and the marginal portion of said laminated plate and the inner wall of the tapped hole are formed to have a closed structure by bending the inner plate and/or the outer plate to attain a direct contact with each other, so as to prevent the outflow of the damping resin material, and said inner wall of the tapped hole of the closed structure works as a stopper for hooking the head of the screw inserted through the tapped hole.
Thus, the present invention prevents outflow of the damping resin material and loosening of the screw fixing the cover to the case by the closed structure wherein the marginal portion of the laminated plate and the inner wall of the tapped hole are bent to directly contact with each other.
Moreover, said structure wherein the marginal portion of the laminated plate and the inner wall of the tapped hole are formed by bending the inner plate and/or the outer plate results in larger bending/torsional stress of the bent portions, thereby improving the rigidity of the whole cover.